2. 3.1 An overview of genetic possesses 3.2 The basis of hereditary 3.3 DNA replication 3.4 RNA and protein synthesis 3.5 Gene expression

3. Genetics – science of hereditary Genome – the genetic information of a cell Chromosomes – structures containing DNA that physically carry hereditary information Genes – segment of DNA (except some viruses contain RNA) Base pair – consist of A(adenine), G (Guanine), T (thyamine) and C (cytosine)

13. Process where one parental of double stranded DNA will split into 2 daughters dsDNA The copies are exactly the same and doesn’t involve in protein production There will be free-nuclotides that available surround the cells that permits the replication process At this time, the new stands will copy it oppositely as pairing the bases in parental DNA, A with T and C with G, from 5’ to 3’, will be copied as 3’ to 5’ The process where induce by DNA polymerase The point at which the replication occur are called as replication fork

15. The new daughter DNA will have one old strand and one newly replicate DNA and this is called as semiconservative replication In special case like in some bacteria, E. coli, the process is bidirectionally around the cromosome. There will be 2 forks move oppositely away from the origin of replication

17. Transcription and translation

18. Synthesis of a complementary strand of RNA from DNA template As your know, there are three RNA in bacterial cell: messenger RNA, ribosomal RNA and transfer RNA Ribosomal RNA (rRNA) – integral component in ribosome producing protein Messenger RNA (mRNA) – carries the coded information for making specific proteins from DNA to ribosomes

20. In transcription, the mRNA strands will copy the specific strands in DNA template The component of nucleic acid bases will be produce in the mRNA pairing the bases in DNA template, for example, a G with C, via versa However in RNA, there are no T so they replace it with U that will be paired with A the DNA strand have 3’ and 5’ ends, so mRNA strand will start copy the bases oppositely, example if the DNA strand start from 3’ and end with 5’, 3’ – ATGCCTA – 5’, the mRNA will start copy and producing 5’ and end up with 3’, 5’ – UACGGAU - 3’

22. The transcription process can only occur with present of RNA polymerase enzyme and supply of RNA nucleotides The process begins when RNA polymerase binds to the DNA at site called promoter The transcription continues until the RNA polymerase reaching the site in DNA called terminator mRNA will become a intermediate storage of DNA information before the translation process take place

23. Translating the ‘language of nucleic acid’ to the ‘language of protein’ ‘language’ of mRNA is in the form of codons, 3 nuclotides consider as 1 codon and coded for 1 specific protein, eg. UAG, GCC, UGG There are 64 possiblity of codon but only 20 types of amino acid are synthesize It is due to the degeneracy situation where some protein coded by more than 1 codon

24. Sense codon – code for amino acid Nonsense codon – also called as stop codon, will stop the translation process

26. Transfer RNA (tRNA) – will recognize the specific codon and transport the particular amino acid tRNA has an anticodon which are used to read the codon in the mRNA strands Most probably the sequence in tRNA now are similar with the origin strand (DNA template) Basically in the DNA genes itself compose of exon (seq that expressed) and introns (seq that do no encode protein) All the introns will be removed by small nuclear ribonucleoproteins ( snRNPs) and combine all the exons together

27. Repression Induction The Operon Model of Gene Expression

28. Most of microbial metabolic reaction need enzymes Some enzymes are needed in a big amount through out the bacterial life as a living demands, for example the glucose product (enzymes of glycolysis) In other cases, the enzyme where only needed in a particular amount and that is why the operon system present

29. Inhibits gene expression and decreases the synthesis of enzymes Prevent from overbundance of an end product of metabolic pathway The protein use to decrease the rate is known as repressor It has ability to block RNA polymerase The default position of repressible gene is on

30. Turns on the transcription of a gene The substance involve known as inducer The enzyme that are synthesized in the present of inducer are inducible enzymes Eg. Enzyme β-galactosidase that split lactose to glucose and galactose for E.coli

31. Introduce by Francois Jacob and Jacques Monod in 1961 To account the regulation of protein expression Gene that determined the surface of protein is known as structural genes In lac operon, there are two short DNA segment known as promoter and operator

32. Promoter – region of DNA where RNA polymerase initiate transcription Operator – as a traffic light that instruct the structural genes to be transcribed Operon – consist of operator, promoter and three structural genes